1. Field of Invention
The present invention relates to a modified stem cell, a homogeneous population of modified stem cells committed to differentiate to the same specific phenotype of stem cells, to a method for producing single identifiable stem cells committed to differentiate to a specific phenotype and to a method for the identification and selection of embryonic, foetal or adult stem cells that are committed to differentiate into a specific type of cell for obtaining homogeneous populations of stem cells.
2. Description of Related Art
Currently, stem cells in a sample of different cells can only be isolated as a heterogeneous population of cells, i.e. as a pool of many cells with the potential to differentiate into different types of cells (for example, hematopoietic and non-hematopoietic cells from bone marrow aspirate, umbilical cord blood or blood samples). Some “rough” selection or enrichment can be done by using antibodies that recognize cell surface antigens present on some of these heterogeneous cell populations (for example CD34 or CD133). Once these antibodies have reacted with the cells, these cells (defined as CD34 or CD133 positive cells) can be isolated by FACS (the antibody has a fluorescence marker) or by magnetic selection (using the MACS technology from Miltenyi Biotec). However, because of the fact that these antigens (which react with the CD34 or CD133 antibodies) are present on different cells, such procedures result also in heterogeneous stem cell populations although a partial enrichment (or selection) will have been done following these procedures.